Naga

The naga fireballs, also called Mekong lights, are glowing red balls that people say rise out of the Mekong River in Thailand and Laos and shoot up into the air. Local people link them to the phaya nak, a giant serpent called a naga in Buddhist and Hindu stories. They are usually reported around the night of Wan Ok Phansa, which marks the end of the Buddhist rains retreat in late October.

Observers say the balls are reddish, from small sparkles up to the size of a basketball, and rise a couple of hundred metres before vanishing. Until the mid-1980s locals called them 'ghost lights', when the local council officially renamed them after the naga. This page separates what people say they see from what investigations suggest.

The legend

In Southeast Asian tradition the naga is a serpent-like water being and a powerful spirit. In the Mekong story, the great naga is said to live in the river and send up the lights. Reports come mostly from a stretch of river about 250 km long, centred near Phon Phisai in Thailand, and each year crowds gather to watch during the Phayanak Festival.

What investigators found

Explanations are debated. A 2002 television documentary showed soldiers on the Lao bank firing tracer rounds into the air, and a Thai biologist who studied footage concluded that flare guns could create the effect. Scientists reject the idea of natural burning gas, because such fireballs would not stay lit at those speeds. A 2021 Lao investigation found no sign of anyone firing weapons that night, so the question is still open.

On the globe

Look for the Mekong River on the border of Thailand and Laos.